Frame content independent stripping for token rings

A frame content independent stripping (FCIS) algorithm for token rings is described that can be used by source-routing bridges due to its simplicity and the fact that the resulting size of the fragments remaining on the ring is very small. The FCIS algorithm counts the number of outstanding frames that a station has transmitted but not yet stripped from the ring and in addition places a global delimiter such as a void frame at the end of the transmission of the information frames. The station then stops stripping when either the count goes to zero or when the void frame or token is received by the station. The algorithm is simple to implement and does not place any topological restrictions on the network. It also allows for interoperation with stations which do not implement the FCIS algorithm. With the FCIS algorithm, frames are stripped at the earliest possible moment. It is shown that the combination of both the count and void is necessary for an FCIS algorithm by demonstrating that the inclusion of either just the void or the count could result in considerable overstripping of frames on the ring due to errors on the ring. The void frame adds a total of 28 bytes of overhead to every transmission opportunity at a participating station.<
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